Rule-based systems are known which use rules, typically "If-Then" sequences, to automatically process or "filter" signal groups transmitted as messages in a computer environment or network. Such systems are generally implemented in the context of electronic mail facilities. The application of rules or the occurrence of an action is triggered upon selected criteria being met. Upon the occurrence of a received and stored mail message satisfying specified conditional criteria set forth in the "If" portion of the statement, such as the mail message being addressed from a selected addressor, the "THEN" portion of the rule or rule set will invoke some action, in some instances directing signal groups comprising the mail message to a designated file or user area. In known systems, the "If-Then" sequences can be constructed using connectors and Boolean operators resulting in relatively complex combinations within and among fields of the sequence.
In one system (ISCREEN), described in A Rule-Based Message Filtering System by Stephen Pollock published in ACM Transactions on Office Information Systems, Vol. 6, No. 3, Jul. 1988, pages 232-254, electronic text mail messages are screened, decisions are made and actions taken in accordance with rules defining procedures typically implemented as part of the manual processing of information generated in an office. A user invokes a rule editor to create rules for providing instructions to the system. The rules include conditions which describe values associated with attributes of a mail message, such as who the mail message is from and/or what it is about. The rules created by the user further include actions which describe what is to be done with mail messages that match the user specified conditions. Typical actions, which in this known implementation are functions of the underlying mail messaging system, include forwarding, filing and deleting the mail message(s).
A special purpose editor invoked by the user to define rules, disadvantageously requires that a specific rule format be learned and adhered to by the user. Specified rules can only be triggered on matching mail message criteria and cannot be triggered based upon the timing of an event, such as the expiration of a time interval. Further, the system requires extensive parsing of user-specified instructions to detect instruction conflicts, completeness and consistency.
Another known system (Object Lens), disclosed in Object Lens: A `Spreadsheet` for Cooperative Work, by Kum-Yew Lai et al published in ACM Transactions on Office Information Systems, 1988, provides various templates for various semi-structured objects which users define and modify to represent information about, among other things, people, tasks, products, and mail messages. Users can create displays to summarize selected information from the semi-structured objects in table or tree formats. A template-based user interface, permits users to interface with an object-oriented data base to see and change objects via interaction with familiar forms or templates. The user, via the templates, constructs conditional rules comprising "If" conditions, which upon satisfaction "Then" result in user-specified actions taking place in accordance with the specified rule(s). The "If-Then" rules can be used to group objects together and can be automatically invoked as "semi-autonomous agents" or methods invoked by the system without user intervention, specified by the user to process information in different ways. Users can create these rule-based agents to be triggered upon the condition of an occurrence, in particular upon receipt of a new mail message. Upon the "If" portion of the rule being satisfied, a further set of rules is applied to a specified collection of objects, semi-autonomously (i.e., automatically but under control by a human user).
However, limited flexibility is provided by this system which only tests occurrences as a conditional ("If") component of a rule. Considerable complexity and inefficiency is also inherent in the system which requires compound conditions ("Ifs") for event triggering, because in addition to every mail message being tested for an occurrence or event which satisfies a first rule, the mail messages must be further tested for other criteria to be satisfied before invoking the action ("Then") portion of the rule.
In addition to having limited event driven capability that results in inflexible and inefficient processing of mail messages, and requiring a user to learn fairly complex rule design and construction schemes, known systems do not have a capability to invoke or "launch" known applications via an event selective rule mechanism.